兔髓核摘除术后施术椎间隙的组织学与影像学变化观察

The histological and radiological changes of rabbit intervertebral space after removal of nucleus pulposus

目的：观察兔髓核摘除术后施术椎间隙的组织学及影像学改变,探讨腰椎间盘突出症患者术后复发的原因,以期为临床预防术后复发提供实验依据。方法选取新西兰大白兔18只,均经左后外侧入路用注射器抽吸 L4/5椎间隙的髓核组织,L3/4椎间隙不做任何处理。分别于术后4、8、12周3个时间点按数字表法随机抽取6只实验兔行数字化 X 线摄影检查、MRI 检查,观察 L3/4、L4/5椎间隙高度指数（DHI）、手术前后 DHI 变化（DHI%）以及改良 Thompson 分级的变化情况；然后处死动物,取出 L3/4、L4/5椎间盘,采用免疫组织化学 SP 染色法,显微镜下观察椎间盘中Ⅰ、Ⅱ、Ⅲ、Ⅵ型胶原纤维改变情况及4种胶原纤维的视野阳性率。将18只兔 L4/5的各项指标观察数据纳入观察组,L3/4的各项指标观察数据则纳入对照组,并对不同时间点2组间数据进行对比分析。结果（1）数字化 X线摄影检查：观察组、对照组 DHI%随时间延长均呈下降趋势,差异均有统计学意义（F观察组=46.292, F对照组=4.251,P 值均〈0.05）；观察组各时间点 DHI%均明显低于对照组,差异均有统计学意义（t 值分别为5.961、6.660、9.122,P 值均〈0.05）。（2）MRI 检查：观察组椎间隙信号强度随时间延长呈逐渐降低趋势,对照组椎间隙信号强度改变不明显。按改良的 Thompson 分级标准,观察组椎间隙信号强度分级呈逐渐升高趋势,不同时间点间比较差异有统计学意义（Hc =9.142,P 〈0.05）；而对照组内不同时间点改变不明显,差异无统计学意义（ Hc =0.611,P 〉0.05）；对照组各时间点椎间隙信号强度分级明显低于观察组,差异均有统计学意义（T 值分别为2.227、2.667、3.090,P 值均〈0.05）。（3）免疫组化染色显示：Ⅰ、Ⅲ、Ⅵ型胶原纤维在术后4、8、12周视野阳性率逐渐增高,差异均有统计学意义（χ^2值分别为9.818、9.451、10.620, P 值均〈0.05）,而Ⅱ型胶原视野阳性率无明显变化,差异无统计学意义（χ^2=0.328, P 〉0.05）。结论兔椎间盘髓核摘除术后施术椎间盘异常的组织修复会导致施术节段脊柱不稳、椎间盘退变及椎间隙抗压能力下降,这些变化均可能与腰椎间盘突出症患者髓核摘除术后症状复发密切相关。

Objective To observe the changes and imaging operation vertebral histology of rabbit nucleus pulposus after surgery. To explore causes of postoperative recurrence in patients with herniation of lumbar intervertebral disc. To provide experimental evidence for prevention of postoperative recurrence.Methods Eighteen New Zealand rabbits were underwent left posterolateral approach with a syringe suction L4 / 5 intervertebral nucleus pulposus of intervertebral space, without any treatment L3 / 4 . Six rabbits were randomly divided into time points 4, 8 and 12 weeks according to the digital. The L3 / 4 , L4 / 5 disc height index （DHI）, the changes of DHI （DHI% ） and changes of Thompson grade were observed by X-ray and MRI examination after 4, 8, 12 weeks, respectively. Then sacrificed animal, removed the L3 / 4 , L4 / 5 disc, using immunohistochemical SP staining to observe the changes of L3 / 4 , L4 / 5 disc typeⅠ, type Ⅱ, type Ⅲ, type Ⅵ collagen fiber under microscope. The positive rate of collagen fiber of 4 kinds of view was compared. The indexes of 18 rabbits L4 / 5 as the observation group, the indexes of L3 / 4 as control group, Results （1） X-ray inspection： The observation group and the control group, DHI% decreased with the time prolonged, the difference had statistical significance. （ Fobservation group = 46. 292, Fcontrol group = 4. 251, all P values 〈0. 05）. The observation groups at each time point in DHI% were significantly lower than the control group,＆amp;nbsp;the difference was statistically significant（ t = 5. 961, 6. 660, 9. 122, all P values 〈 0. 05）. （2） MRI inspection： The observation groups of intervertebral space of signal intensity were gradually decreased with the time prolonging. The control group had no significant change in signal intensity of intervertebral space. According to Thompson grading standards improved, the observation group intervertebral disc signal strength grading showed a trend of rising and compare the differences between different time points were statistrcally significant（Hc = 9. 142, P 〈 0. 05）, while the control group at different time points within the change was not obvious, there was no significant difference （ Hc = 0. 611, P 〉 0. 05）. The control signal strength grading vertebra clearance group at each time point was significantly lower than the observation group, the difference was statistically significant（T was 2. 227, 2. 667, 3. 090, respectively, all P values 〈 0. 05）. （3） Immunohistochemical staining showed that the positive rate of type Ⅰ, Ⅲ, Ⅵ collagen fiber in the postoperative 4, 8, 12 weeks of field of vision gradually increased, the difference had statistical significance （χ^2 were 9. 818, 0. 328, 9. 451, 10. 620, respectively, all P values 〈 0. 05）, the positive rate of type Ⅱcollagen field had no obvious change, there was no significant difference （ χ^2 = 0. 328, P 〉 0. 05 ）.Conclusions The positive rate of type Ⅱ collagen field has no obvious change, there is no significant difference. Both drop operation of disc degeneration and vertebral compressive capacity gap are possible in patients with resection of nucleus pulposus of closely related to recurrence of symptoms after the operation of lumbar disc herniation.